Recently I had a number of growths coming from some fairly new live rock (few months). At first I was not concerned, but it seems to be spreading. Is has a jelly like base, and brown stringy tops, some forming pod (mushroom) like tops. When distrubed, it retreats into the rock, and seems to sting corals next to it. Does anyone know what this is, and is it bad for a reef and fish aquarium (225 gals).